Mycoplasma genitalium (MG) is a sexually transmitted infection (STI) caused by a small bacterium found on the mucous cells of the human urinary and genital tracts, including the cervix, urethra, and rectum. Many individuals with MG experience no symptoms, unknowingly transmitting the infection. Untreated MG can lead to various complications, including urethritis, cervicitis, and pelvic inflammatory disease (PID). The increasing prevalence of MG makes proper diagnosis and effective treatment important for managing its spread and preventing associated health issues.
Standard Treatment Regimens
Initial treatment for Mycoplasma genitalium involves a two-step antibiotic approach to improve effectiveness and reduce the risk of resistance. This begins with doxycycline, 100 mg taken twice daily for seven days. Doxycycline lowers the overall bacterial load, which helps prepare the infection for more targeted eradication by the subsequent main antibiotic.
Following doxycycline, an extended regimen of azithromycin is prescribed for macrolide-susceptible infections. The dosage is 500 mg on the first day, followed by 250 mg once daily for the next four days, totaling 2.5 grams. Adhering to the full course of both antibiotics is important for successful treatment outcomes. Common side effects include gastrointestinal issues such as nausea.
During the entire treatment period, it is important to abstain from sexual activity to prevent transmitting the infection to partners and to avoid reinfection. A healthcare professional should be consulted for a personalized treatment plan, as individual circumstances and local resistance patterns influence the best approach.
Addressing Treatment Failure and Resistance
When initial antibiotic treatment for Mycoplasma genitalium does not resolve the infection, it indicates antibiotic resistance. This is a growing concern for MG, as the bacteria can develop mutations in its DNA that render common antibiotics ineffective. Resistance to macrolides, such as azithromycin, has become widespread, with prevalence rates for resistance markers ranging from 44% to 90% in some regions. This can lead to persistent symptoms or a positive retest even after completing the prescribed medication.
For macrolide-resistant MG or when first-line treatment fails, alternative antibiotic regimens are necessary. Moxifloxacin, a fluoroquinolone, is used, prescribed as 400 mg once daily for 7 to 14 days. While moxifloxacin has shown high cure rates, resistance to this antibiotic is also emerging in some areas. Other options for highly resistant strains, particularly after moxifloxacin failure, may include minocycline or pristinamycin, though their availability can be limited.
Reasons for treatment failure extend beyond antibiotic resistance and can include not completing the full course of medication, or reinfection from an untreated sexual partner. When available, susceptibility testing can help guide treatment decisions by identifying which antibiotics will be most effective against the specific strain of MG present, significantly improving cure rates.
Ensuring Successful Outcomes
After completing antibiotic treatment for Mycoplasma genitalium, several steps are important to confirm eradication and prevent future infections. An important step is undergoing a Test of Cure (TOC), a follow-up test to ensure the infection has been successfully cleared. This test should be performed at least three to four weeks after treatment completion to avoid false positive results from residual bacterial DNA. A negative TOC confirms eradication.
Another important aspect of successful management involves notifying and treating sexual partners. Since MG is sexually transmitted, partners should be informed and encouraged to get tested and treated, even if they do not have symptoms. This helps prevent reinfection of the treated individual and limits further spread within the community. Treating current sexual partners with the same therapy as the index case is recommended.
To minimize the risk of reinfection, adopting safe sex practices is advisable. Consistent and correct use of condoms during sexual activity significantly reduces the likelihood of acquiring MG again. These post-treatment measures are essential for ensuring a lasting cure and controlling the spread of Mycoplasma genitalium.